58,447 research outputs found
Use of a coupled soil-root-leaf model to optimise phosphate fertiliser use efficiency in barley
No full textFiles used to compute the figures for the paper Heppell, J., Payvandi, S., Talboys, P., Zygalakis, K., Langton, D., Sylvester-Bradley, R., Edwards, A.C., Walker, R., Withers, P., Jones, D.L. and Roose, T. (2016) Use of a coupled soil-root-leaf model to optimise phosphate fertiliser use efficiency in barley. Plant and Soil, 1-29. (doi:10.1007/s11104-016-2883-4)</span
How changing root system architecture can help tackle a reduction in soil phosphate (P) levels for better plant P acquisition
No full textThe readily available global rock phosphate (P) reserves may run out within the next 50-130 years, causing soils to have a reduced P concentration which will affect plant P uptake. Using a combination of mathematical modelling and experimental data we investigated potential plant-based options for optimising crop P uptake in reduced soil P environments. By varying the P concentration within a well-mixed agricultural soil, for high and low P (35.5 to 12.5 mg l-1 respectively, using Olsen’s P index), we investigated branching distributions within a wheat root system that maximise P uptake. Changing the root branching distribution from linear (evenly spaced branches) to strongly exponential (a greater number of branches at the top of the soil), improves P uptake by 142% for low P soils when root mass is kept constant between simulations. This causes the roots to emerge earlier and mimics topsoil foraging. Manipulating root branching patterns, to maximise P uptake, is not enough on its own to overcome the drop in soil P from high to low P. Further mechanisms have to be considered to fully understand the impact of P reduction on plant development
Ultra-fast time-lapse synchrotron radiation CT imaging of compressive failure in unidirectional glass fibre-epoxy composite
No full textThis series of ultra-fast X-ray computed tomography datasets were acquired on the TOMCAT beamline at the Swiss Light Source by the composite group at Henry Moseley X-ray Imaging Facility (within the Henry Royce Institute @Manchester).
The experiment was designed to help understand the catastrophic failure of unidirectional fibre reinforced composites under compression, as part of Ying Wang's PhD project (Damage Mechanisms Associated with Kink-Band Formation in Unidirectional Fibre Composites) supervised by Prof. Philip J. Withers.
A notched unidirectional glass fibre-epoxy composite specimen was loaded in-situ under compression in a tension/compression rig developed at INSA-Lyon. An initial scan of the composite gauge section was acquired before loading (GFRP_Initial.zip). During the in-situ loading process, the composite specimen was imaged statically at 200 N (GFRP_Static_200N.zip) and 600 N (GFRP_Static_600N.zip), after which the acquisition mode was changed to continuous streaming in order to capture the final stages immediately leading up to failure, at 876 N (GFRP_Continuous_876N.zip), 893 N (GFRP_Continuous_893N.zip), 895 N (GFRP_Continuous_895N.zip), and right after collapse (at 79 N, GFRP_Failed.zip).
The CT acquisition speed attained 1 tomogram per second. The voxel size of the reconstructed CT data-sets is (1.1 μm)3.
For use of the data, please cite the DOI of the repository and the relevant papers -
http://doi.org/10.5281/zenodo.2597497
Wang, Y., Emerson, M. J., Conradsen, K., Dahl, A. B., Dahl, V. A., Maire, E. and Withers, P. J. (2021). Evolution of Fibre Deflection Leading to Kink-band Formation in Unidirectional Glass Fibre/Epoxy Composite Under Axial Compression. Composites Science and Technology. (Under Review)
Emerson, M. J., Wang, Y., Withers, P. J., Conradsen, K., Dahl, A. B., and Dahl, V. A. (2018). Quantifying fibre reorientation during axial compression of a composite through time-lapse X-ray imaging and individual fibre tracking. Composites Science and Technology, 168, 47-54.
Wang, Y., Garcea, S. C., Lowe, T., Maire, E., Soutis, C. and Withers, P. J. (2016). Ultra-fast time-lapse synchrotron radiographic imaging of compressive failure in CFRP. In ECCM16-16th European Conference on Composite Materials, Munich, Germany.
Garcea, S. C. , Wang, Y. and Withers, P. J. (2018). X-ray computed tomography of polymer composites, Composites
Science and Technology (156), 305-319.
Wang, Y., Garcea, S. C. and Withers, P. J. (2018). Computed Tomography of Composites in Comprehensive Composite
Materials II (7), 101-118. Eds. Beaumont PWR, Zweben CH. Elsevier.We acknowledge the Engineering and Physical Science Research Council (EPSRC) for funding the Henry Moseley X-ray Imaging Facility within the Henry Royce Institute through grants (EP/F007906/1, EP/F001452/1, EP/I02249X, EP/M010619/1, EP/F028431/1, and EP/M022498/1). PJW acknowledges support from the European Research Council grant No 695638 CORREL-CT
P-equilibrium fertilization in an intensive dairy farming system: effects on soil-P status, crop yield and P leaching
No full textIn the coming decade, European dairy farms are obliged to realize a balance between phosphor (P) inputs to their farmland (in inorganic fertilizers and manure) and outputs (in crop products), the so-called P-equilibrium fertilization. The objective of the present study is to analyze the long-term effects of P-equilibrium fertilization on soil-P status (total soil-P and available soil-P), crop yield and P leaching on dry sandy soil, using data from experimental dairy farm ‘De Marke’, where P-equilibrium fertilization has been applied since 1989. For grassland, P availability is expressed in P-Al and for arable land in Pw. Total and available P status were monitored in the upper topsoil (layer 0–0.2 m). Total soil-P was also monitored in the lower topsoil (layer 0.2–0.4 m) and in the subsoil (0.4–0.6 m). From 1989 to 2006, Pw and P-Al (means of all farmland) decreased by 26 and 25%, respectively. In the same period, mean total-P content of the farmland decreased by 16%. There was a large variation in initial P status (1989) of the various plots. The rate of decline in all soil-P indicators was positively correlated to their initial values. In plots with the lowest initial values, P status did not change, while in plots with high initial values it tended to stabilize at lower levels. At equilibrium-P fertilization, Pw is estimated to stabilize at 20. This is lower than the recommended P status of Dutch soils used for maize cropping. P-Al is estimated to stabilize at 30–40, which corresponds to the current recommendations for grassland. The data show that at P-equilibrium fertilization, soil available-P status is higher in a maize-ley rotation than in permanent grassland. The decline in total P and available P did not affect crop yield, nor did it affect the P concentration in groundwater, but at ‘De Marke’, P emission to groundwater is generally low. The results obtained suggest that P-equilibrium fertilization can be compatible with efficient crop productio
Measurement of the ratio of prompt χ c to J / ψ production in pp collisions at √s = 7 TeV
Full text linkThe prompt production of charmonium χ c and J / ψ states is studied in proton-proton collisions at a centre-of-mass energy of √s = 7 TeV at the Large Hadron Collider. The χ c and J / ψ mesons are identified through their decays χ c → J / ψ γ and J / ψ → μ + μ - using 36 pb - 1 of data collected by the LHCb detector in 2010. The ratio of the prompt production cross-sections for χ c and J / ψ, σ (χ c → J / ψ γ) / σ (J / ψ), is determined as a function of the J / ψ transverse momentum in the range 2 < p T J / ψ < 15 GeV / c. The results are in excellent agreement with next-to-leading order non-relativistic expectations and show a significant discrepancy compared with the colour singlet model prediction at leading order, especially in the low p T J / ψ region
Predicting body cell mass with bioimpedance by using theoretical methods: a technological review
No full textThe body cell mass (BCM), defined as intracellular water (ICW), was estimated in 73 healthy men and women by total body potassium (TBK) and by bioimpedance spectroscopy (BIS). In 14 other subjects, extracellular water (ECW) and total body water (TBW) were measured by bromide dilution and deuterium oxide dilution, respectively. For all subjects, impedance spectral data were fit to the Cole model, and ECW and ICW volumes were predicted by using model electrical resistance terms RE and Rt in an equation derived from Hanai mixture theory, respectively. The BIS ECW prediction bromide dilution was r = 0.91, standard error of the estimate (SEE) 0.90 liter. The BIS TBW prediction of deuterium space was r = 0.95, SEE 1.33 liters. The BIS ICW prediction of the dilution-determined ICW was r = 0.87, SEE 1.69 liters. The BIS ICW prediction of the TBK-determined ICW for the 73 subjects was r = 0.85, SEE = 2.22 liters. These results add further support to the validity of the Hanai theory, the equation used, and the conclusion that ECW and ICW volume can be predicted by an approach based solely on fundamental principles
When was that? A chronological dictionary of important events in Newfoundland down to and including the year 1922
No full textContains alphabetical entries for various subjects such as individuals, places, events, topics, and ships. -- Includes appendix: St. John's over a Century Ago: Living Conditions in Newfoundland, as revealed in the first volume of The Royal Gazette / J.W. Withers, 1907 (p. 143-163). This is an essay on the state of St. John's in 1807 based on information in the Royal Gazette
Letter from Carl Hayden to P. J Moran
No full textLetter from Carl T. Hayden to P. J. Moran concerning the alignment of the road to Bright Angel Trail
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